Cognitive Structure Determination of Prospective Science Teacher via Word Association Test

This present study aims to determine the prospective science teachers’ cognitive structure about the domain of buffer solution with word-association test. The research was conducted in the spring semester of the academic year of 2018-2019 with a sample of 71 prospective science teachers in the department of science teaching program at a state university in central Anatolian region in Turkey. To be able map the structures, response frequencies were used. Nine of the 71 prospective science teachers are male and the rests are female. This is a qualitative descriptive study. The word-association test contains eight stimulus words to collect data about prospective science teachers’ cognitive structure for the domain of buffer solution. The opinions of four instructors who has already taught chemistry III (analytical chemistry in content) course to the prospective science teachers were obtained for the appropriateness of the stimulus words used in the present study. The gained data was analyzed by using response frequency map method. The obtained findings have been discussed on the base of the related studies and some suggestions have been made

A Novel MPTHP Modified Glassy Carbon Sensor Electrode: Investigation of Electrochemical Behaviors and Determination of Cu (II) Ions in Drinking Water Sample

In the present work report, 2-methyl-6-((2-(4-(3-methyl-3-phenylcyclobutyl)thiazol-2-yl)hydrazono)methyl) phenol (MPTHP) has been newly synthesized and characterized. The new molecule has been used to modify the glassy carbon (GC) electrode surface through the alcohol oxidation method due to –OH group on its structure. MPTHP modified GC (MPTHP/GC) electrode has been used as a chemical sensor electrode for the quantitative determination of Cu (II) ions. Following the modification process, the surface characterization process of the modified electrode has been carried out by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). In this work, Cu (II) ions have been quantitatively determined by using differential pulse voltammetry (DPV) technique. A quite low detection limit (based on 3sbl/m) for Cu (II) using developed sensor electrode was found to be as 1.0x10-9 M. For the calibration curve, solutions of Cu (II) ions changing from 1.0x10-9 M to 1.0x10-3 M have been prepared using Britton-Robinson (BR) buffer solution at pH 5. The developed sensor electrode has been applied to tap water sample for the quantitation of Cu (II) ions and the amount of Cu (II) was determined as 4.07 x 10-9 M in this sample